Your 40s are considered a mid-point, the top of the hill. It's a big milestone - but you've got miles yet to go! Don't let body changes and health hazards send you downhill.

The healthiest you, in your 40s and beyondWe can't deny it: time passes, and our bodies change. Our day-to-day health is kind of like the weather. Like sunny days or passing storms, colds come and go. So do sniffles, aches and pains, and pimples and blisters. Our overall health, though, is more like the climate. It's an accumulation of lots of different factors - genetics, chance, and the lifestyle choices we make - and has more impact on our lives in the long run.

Some of the factors that affect our health are out of our control, like our family's medical legacy. If your mother or sister have had breast cancer, you might be more likely to have breast cancer, too. Accidents, injuries, and genetically unforeseen conditions can sideswipe us and set our health off-balance, too.

But we can control the lifestyle choices we make, and these choices certainly do accumulate and either enrich or endanger the quality of health we enjoy through the years of our lives. Decisions you make, like whether to smoke or not, what sort of foods you eat, and how much physical activity you fit into your life, may make or break your health.

Each one of us is a unique specimen, and the aging process will touch us each in different ways. In general, to be the healthiest you at any age, you will need to understand the ways your body may change. You also need to keep up with a few routine preventive health screenings and integrate beneficial habits into your life. Time passes, so make the most of the time you have, no matter what your age.

Your 40s: body basicsWhenever we hit a decade-marking age - 10, 20, 30... 40 - we supposedly go through some imagined transition, like we've just crossed some important threshold. But what makes 40 feel so different? Why do we perceive 40 as the top of the proverbial "hill," that hill we supposedly roll down into the valley of old age? In a word: estrogen.

For women, much of the force of 40 comes from the fact that this is the decade in which our fertility declines. It's the time when many women move through perimenopause, the years leading up to full-blown menopause. Some women skip suddenly to menopause in a matter of 2 years or so, while others note subtle and overt changes across years, even a decade.

During perimenopause, estrogen levels fluctuate, triggering switches in menstrual cycles - they may be lighter, shorter, heavier, or longer, the intervals between periods may change, but they'll likely be different than they've been before. Irregular ovulation makes it much more difficult to become pregnant. While two-thirds of women over the age of 40 experience fertility problems, those who do become pregnant also face higher risk of complications (e.g., high blood pressure or diabetes during pregnancy), miscarriage, birth defects, and low birth weight.

These hormonal shifts can bring menopause-related symptoms, including hot flashes and sleep difficulties with or without night sweats. Mood swings, irritability, and depression, more likely linked to stress or lack of sleep than hormonal changes, may also arise.

Dropping estrogen may mean less vaginal lubrication, which can make sexual intercourse difficult and possibly painful and also make a woman more vulnerable to urinary and vaginal infection.

Estrogen loss has also been linked to bone loss, making it all the more important to support your bones via strength training and adequate calcium intake (1000 mg per day). And as estrogen dips, heart disease risk can increase, due to boosts in bad cholesterol, diminished elasticity of arteries, and accumulation of belly fat.

That belly fat - sometimes jokingly called the "meno-pot" - can increase a woman's risk of heart disease, diabetes, and cancer. And it is stubborn fat, too. Even with regular exercise, it can be tough to keep it - and your overall weight - in check. That could be because a woman's caloric needs change as she gets older, even if her activity levels don't. Basal metabolic rate also declines little by little with each decade of life, so fat-burning requires extra effort.

Fat-burning is not purely cosmetic, and neither are some of the other changes to the appearance of a woman's body as she ages. Signs of agingmay become more apparent, in the form of wrinkles, dry skin, loosened skin around the neck, and crinkles and furrows around the eyes and mouth. Hair may show more white or grey and become thinner.

A woman in her 40s may also note changes in the way her breasts look. The breasts are fatty tissue and contain no muscles. It is an underlying network of connective tissue called the "Cooper's ligaments" - along with a well-fitted bra - that support breast tissue. As a woman ages, these ligaments become less taut, which leads to sagging.

A whole host of other health risks spring into a woman's peripheral awareness in this decade, too. Osteoarthritis, a joint disorder that usually affects the hips, knees, feet, and spine, tends to strike women in their 40s and 50s, although it can occur at any age. Risks for breast, ovarian, and uterine cancer rise in this decade, too, with the risk being greater for women in their 50s for breast and ovarian cancers.

Weakened pelvic muscles may play a role in urination issues like incontinence, and in some women a condition called pelvic prolapse is to blame. Women who are obese or have given birth in the past are more susceptible. Excess weight may also make a woman more vulnerable to uterine fibroids, non-cancerous tumours that are more common as a woman moves toward menopause.With all that is known about living a healthy lifestyle and preventing disease, women need not worry about the whole over-the-hill thing. Read "Your 40s: healthy habits" for the many ways women can make their 40s fantastic.

Eat your age. By this time in your life, you know which foods you love and loathe, but hopefully your mind remains open to new possibilities on your plate. That may mean trying healthy, functional foods you've never tried before. And it will likely mean eating less than you've ever eaten before. That's because as you get older, you need fewer calories per day, meaning you should consume fewer calories. Since the body's metabolism naturally slows down over time, enforcing this calorie cut could help you trim the fat, so to speak, and keep weight from piling on.

Favour functional foods. Do you live to eat or eat to live? Why choose? You can get the best of both if you choose foods that please the palate and emphasize the 40-something must-have nutrients. That way, you won't have to sweat the details of how many milligrams or micrograms you get of this vitamin or that mineral. A balanced yet varied diet rich in fruits, vegetables, whole grains, and lean protein sources will likely also be filled with bone-boosting calcium and its companion vitamin D and the fibre you need to support your heart and digestive health.

Know your numbers. Though it's less stress to not think about the nitty-gritty details of your recommended daily intake of individual nutrients, it doesn't hurt to have the numbers in the back of your mind - or printed up and stuck on your fridge. Some of the vital vitamin and nutrient numbers to know:

Calcium and vitamin D play a big role in minimizing the bone loss that results when, in your 40s and 50s, your body's estrogen levels fluctuate and eventually fall. Your calcium count should be 1000 mg per day and your vitamin D intake should be 400 IU to 1000 IU per day.

Fat should make up no more than 30% of your total daily calorie count. Make the most of that 30% by opting for the "good" fats - mono- and polyunsaturated fats and omega-3 fatty acids found in fish, nuts, and olive oil.

Your protein tally should be between 10% and 35% of your daily calorie intake.

The magic number for fibre: 25 g, the equivalent of about 5½ apples, but it's more fun to fit in fibre from an assortment of foods, like from beans, popcorn, raisins, a variety of veggies, and whole-grain breads. In general, a healthy adult needs 21 to 38 grams of fibre a day.

Be a body in motion. You may struggle to find time to fit in regular exercise. But every time you do manage to eke out even the shortest workout, your body will thank you a million times over. Just think about how good a burst of physical activity can feel - how you sleep better, how you handle stress with a more level head, and how you buzz with strong, focused energy for work or for play (of all sorts). And of course, a mix of aerobic exercise and strength training will help you maintain a healthy weight, reduce your risk of many chronic conditions, and preserve and build bone strength. Switch old, tired routines for a fresh approach. Trade your jog for an evening at the yoga studio - or vice versa!

Put pickles on the side. If you suddenly find yourself caught between parenting your children and caring for the needs of your aging parents, you're a part of the so-called "sandwich generation." For those stuck in the middle, stress and obligations can quickly pile on. Finding time for you can be a real pickle. So, put the pickles on the side. Set aside a few moments within each week in which you can focus on yourself. You could use your "me-time" to indulge in a vice or put your heart into healthy, relaxing, rejuvenating past-times. Or you might make a to-do list for the sole purpose of crossing off the things you've already accomplished.

Let your beauty shine through. Some signs of age reflect the joy of life lived well - crinkly crows-feet around smiling eyes, lines of laughter around the lips. Others reveal the stress and wear of the tougher moments, like that deep furrow between your eyes or that wrinkled "worry brow" you've got going on. Rather than give in to the temptation to conceal these visible reminders of age - with heavy makeup, or a nip, a tuck, a paralyzing shot to the temple - find ways to highlight your true, actual beauty. Keep your skin supple by drinking plenty of water and eating foods rich in antioxidants. Add antioxidant-infused skincare products to help restore skin that has been marred by sun or stress. Look for products with ingredient names like CoQ10 and vitamins A, C, and E. Apply moisturizer and exfoliate regularly to slough off dull, dry skin. Shield your skin from further solar damage with moisturizing, daily-wear sunscreen. If you feel your skin needs extra help, ask your doctor about prescription medications that may reduce appearance of brown spots, rough skin, and fine wrinkles caused by skin damage.

Your 40s: check-up checklistCheck out this check-up checklist and stay on top of the tests and examinations you need all through your 40s.

Bone density test: When you hit your 40s, you don't need to worry too much about osteoporosis - that is, unless you fall into particular risk categories. Taking certain medications may speed bone loss, and certain medical conditions can compromise bone density as well. Ask your doctor if you are concerned about osteoporosis, especially if it runs in your family.

Diabetes screening: If you are in your 40s, you may be at risk for type 2 diabetes. Your doctor can screen your risk by testing your levels of hemoglobin A1C (a blood test that reflects your average blood glucose levels over the last 3 months) or your blood glucose levels. How often you need to be screened for diabetes will depend on your risk of diabetes. If you are overweight, your risk of diabetes will probably be higher and you should be tested earlier and/or more often. Ask your doctor how often you should be screened for diabetes.

Blood pressure and cholesterol: You're not at too much risk of elevated levels now, especially if you're following healthy heart habits like exercising regularly, eating a nutritious diet, and not smoking. Any time you go in for any health care visit, your blood pressure will be gauged, and you should get a cholesterol work-up every few years. If you fall into certain risk groups, your doctor may screen your levels more frequently or at an earlier age. You may be at risk if you have diabetes or a large waist circumference, or if you smoke.

Pap test and pelvic exam: By the time you've hit 20, you should be having routine pelvic exams and Pap tests every 2 to 3 years. Pap tests screen for cervical cancer, while the pelvic exam allows your health care provider to examine your cervix and vagina and to get a sense of the health of your uterus. Your health care provider might also look for signs of infections.

Breast exam: Breast cancer is a very common cancer among women. Your health care provider may do a clinical breast exam when you go in for your annual Pap test and pelvic exam. Ask your doctor if you should have a clinical breast exam and, if so, how often. You should also become familiar with the look and feel of your breasts so you know what's normal for you. If you fall into a high-risk category for breast cancer, your doctor may suggest you have mammograms in your 40s. Otherwise, mammograms should be done every 2 or 3 years from age 50 to 74 (your doctor will advise you if you still need mammograms after age 74).

Skin check: Anyone at any age can develop skin cancer. In addition to minimizing your risk with healthy sun habits, your health care provider should do a thorough skin check to screen for new or changed moles or marks. You can also do a skin check yourself (or with a helpful partner). Remember the letters ABCDE when looking at skin growths:

Asymmetry (not round)

Border (irregular)

Colour (uneven, changing, different from other moles)

Diameter (larger than a pencil eraser)

Evolving (changing in size, shape, or colour)

If anything seems out of the ordinary or alarming, contact your doctor.

Dental check-ups: Visit your dentist for preventive check-ups and routine cleanings. The frequency of visits will really depend on individual needs, though most authorities on the subject recommend at least once or twice a year.

Eye exams: Even if your vision is 20/20, you should have your eyes examined every 1 to 2 years. After all, optometrists check for other things besides how good your vision is - like signs of glaucoma. If you have a condition like diabetes or high blood pressure, or a family history of vision problems, your optometrist will let you know if you need more frequent eye exams and check-ups.

Immunizations: You think shots are just for kids? Certain vaccinations you received as a child may need to be updated, while other immunizations are available that can protect you from needless health issues. Ask your doctor if you're due for any of these:

Get shots to protect you from measles, mumps, and rubella (MMR)if you've never had the vaccination before. Should you find yourself in certain risk situations, you'd also need the MMR vaccination. Those risky situations include working in health care, attending college, and travelling to certain countries.

The tetanus, diphtheria, and pertussis (Tdap) vaccine is recommended for anyone whose last Tdap shot was more than 10 years ago. Others who should get the Tdap include those who work in close contact with infants, those who plan on becoming pregnant, and those who have received a "dirty" wound (e.g., from a rusted nail).

Each year, get the influenza vaccine. The flu shot is especially important if you have medical conditions that put you at risk of complications from the flu.

Considering world travel? Consider being vaccinated against meningitis and hepatitis A and B, and consult with a travel clinician or your doctor in regards to other risks of particular destinations.

If you never had chickenpox as a youngster, you should get vaccinated against it now. And if you're unsure whether you did, go ahead and get the vaccination, just in case. It's a good idea to get it, too, if you're hoping to get pregnant sometime in the future and don't know if you're immune to chickenpox. Hold off, though, if you're already pregnant (or hope to be within several weeks of vaccination).